提出美元与黄金挂钩的“怀特方案”的怀特确实是苏联间谍吗？怎么被发现的?

是苏联间谍无误。参见司法部公布的调查结果FBI Memorandum identifying Harry Dexter White as agent Jurist。

以下是维诺那计划 (豆瓣)中的正文前图集部分：

怀特开始暴露的起因是1945年二战结束之际美共间谍本特利（Elizabeth Bentley）决定退出组织并向FBI检举美共在华盛顿的情报网，前美共成员钱伯（Whittaker Chambers）在1948年出面指证怀特，FBI根据“维诺那计划”破译的电文（1946年底才破译出来第一份电文）确定美国共谍名单，掌握了怀特从事间谍活动的证据，于是怀特在1948年受到HUAC的质询。棘手之处在于当时FBI局长胡佛出于信息安全考虑而需要对“维诺那计划”（Venona project - Wikipedia）进行严格的保密乃至杜鲁门政府亦不知情，因此最关键的证据由于涉及苏俄在美国密布的庞大情报网，导致这部分证据无法在HUAC上公开，怀特因此得以在HUAC的听证会上口若悬河替自己辩护而暂时脱罪，但几天后心脏病发作，两天后死亡，验尸结果是洋地黄（digitalis）摄入过量。

On August 13, 1948, White testified before HUAC and denied being a communist. After he finished testifying he had a heart attack. He left Washington for a rest on his Fitzwilliam, New Hampshire farm. He had just arrived when he had another heart attack.[50] Two days later, on August 16, 1948, he died, age 55.[51][52] An overdose of digitalis was reported as the cause of death.[53]

曾有人怀疑怀特的死因系为苏联特工制造的一桩针对怀特的灭口行动，但由于缺乏证据最终调查不了了之。事后“维诺那计划”解密的结果显示怀特确实对发展苏联在美国政界的间谍网至关重要，甚至和希斯（Alger Hiss - Wikipedia）一样有政治泄密行为。这方面证据还可以参见KGB档案负责人Vassiliev的记录Alexander Vassiliev’s Notes and Harry Dexter White，其中莫斯科的通讯记录和美国国会证词由黑框部分标出，内容直指怀特的具体活动。

怀特曾经出卖中国，见吕迅著《大棋局中的国共关系》出版-中国社会科学院近代史研究所 第69页谈到：

此外还可以参见回答约翰·肯尼迪（John F. Kennedy）为什么被刺杀？中关于怀特的相关段落。

怀特被确证为间谍是在于“维诺那计划”查实的电文破译后揭示出电文中代号为Jurist的人正是他本人，苏联解体后KGB的解密档案也揭示出他的间谍身份且上线是莫斯科，因此成了莫斯科知晓白宫政治机密的信息源之一（这点是直接证据）。这方面权威著作参考《维诺那计划》（作者是这方面的历史研究专家John Earl Haynes），其中第168页谈到

文中提到的希斯（Alger Hiss - Wikipedia）被HUAC确认为间谍是因为尼克松在HUAC出示了著名的“南瓜文件（Pumpkin Paper）”，但那时已经过了法律规定的10年追诉期，最后无法判间谍罪而只能依法判伪证罪入狱，原因是希斯先前否认自己从事相关间谍活动。

《维诺那计划》第169页还谈到怀特出卖东欧国家，他本人作为美籍立陶宛人积极给苏俄带路，不惜为苏俄吞并立陶宛的举动站台（参见《维诺那计划》的笔记-第169页）：

有意思的是，文中提到的“迟照庭”（音译）经对照英文版（Venona (豆瓣)）和人物履历，可确定是知名TG地下党员冀朝鼎，英文版对照Venona (豆瓣)，p.140

With U.S Government support, arranged through White, Chi returned to Chungking in 1941 to become an official of the Chinese government's finance ministry. There he supplied the Chinese Communists with information and disrupted Chiang Kai-shek's regime from within. When Chiang and his Nationalist government retreated to Taiwan in 1949, Chi stayed on the mainland , openly anouncing his status as a veteran Chinese Communist party operative, and became a senior official of Mao Tse-tung's government.[51]

There are fifteen deciphered KGB messages during the 1944 and 1945 in which White was discussed or which reported information he was providing to Soviet intelligence officers.[52] The KGB mentioned that White offered advice concerning how far the Soviet could push the United States on abandoning the Polish Government-in-exile(Which was hostile to Stalin) and assured the Soviet that U.S.policy-makers, despite their public opposition, would acuiesce to the USSR's annexation of Latvia, Estionia, and Lithuania. White was also a senior adviser to the U.S. delegation at the founding conference of the United Nations in San Francisco in May 1945. During the negotiations on the UN charter he met covertly with Soviet intelligence officers and provide them with information on the American negotiating strategy. He assured the Soviets that "Truman and Stettinius want to achieve the success of the conference at any price" and advised that if Soviet diplomats held firm to their demand that the Soviet Union get a veto of UN actions, that the United States"will agree".[53]。

后面第171页也谈到怀特阻滞美援到达中国以促成战后远东共运形势

原文对照（英文版Venona (豆瓣)，p.142）

In 1942, the U.S. Congress authorized a $500 million loan to Nationalist China. In 1943 the Chinese government asked for a $200 million delivery of gold to be charged against this loan. China's currency was inflating rapidly under wartime conditions, with great damage to that country's economy. A supply of gold to back the currency would assist in slowing inflation, which was rising to ruinious levels. Roosevelt approved the gold loan, and in July 1943 Secretary Morgenthau signed a letter to the Chinese government pledging transfer of the gold.

White, with the assistance of Frank Coe (director of the Division of Monetary Research) and Solomon Adler (Treasury representative in China), opposed carring out the transfer and repeatedly won Morgenthau's support for delaying delivery, arguing that pervasive corruption in the Nationalist government and its failure to adopt financial reforms would result in the gold's doing little good. By July 1945, two years later, only $29 million in gold had been sent to China. Meanwhile, the hyperinflation of this period, more than a thousand percent a year, did immense damage to the Chinese economy and severely weakened the standing of the Nationalist government when civil war with the Chinese Communists resumed at the end of 1945.
……
Morgenthau, however, thought his aides had merely mishandled the gold transfer but were well motivated, and he never suspected that they had an entirely separate agenda from his.[58]

另外，还可以参见wiki词条苏联在美国间谍名单List of Eastern Bloc agents in the United States，其中两个情报网Silvermaster group和Ware group都显示出怀特在共同的名单里，附带说一句Silvermaster也是苏联间谍（就是上文段落中提到的“西尔夫马斯特”），相关调查卷宗和报告参见wiki词条的FBI Silvermaster File的引用来源，原材料参见https://archive.org/details/FB... ：

维诺那文件中的List of Americans in the Venona papers的也提到怀特

Harry Dexter White, Senior U.S. Treasury department official, primary designer of the International Monetary Fund and the World Bank.

怀特的间谍身份除了根据“维诺那计划”的线索确认外，后来还可以根据苏联解体后KGB档案得到印证，相关信息基本吻合，参见Alexander Vassiliev’s Notes and Harry Dexter White， wiki词条也谈到：

This codename was confirmed by the notes of KGB archivist Vasili Nikitich Mitrokhin in his country volume 6, chapter 3, part1, where six key Soviet agents are named. Harry Dexter White is listed as being first "KASSIR" and later "JURIST".[62]

Further evidence of White's complicity as a Soviet agent was gleaned from Soviet archives and KGB operative Alexander Vassiliev. In a book by Allen Weinstein and Alexander Vassiliev, The Haunted Wood: Soviet Espionage in America — the Stalin Era, Vassiliev, a former Soviet journalist and KGB operative, reviewed Soviet archives dealing with White's actions on behalf of the Soviet Union. White assisted Harold Glasser, a Treasury executive and NKVD spy, "in obtaining posts and promotions at Treasury while aware of his Communist ties". Because of White's backing, Glasser survived an FBI background check. In December 1941 the Secret Service forwarded a report to Harry White indicating that it had evidence Glasser was involved in Communist activities. White never acted on the report. Glasser continued to serve in the Treasury Department, and soon began recruiting other agents and preparing briefing reports on Treasury personnel and other potential espionage agents for the NKVD.

参考：

1.维诺那计划 (豆瓣)

2.苏联间谍在美国名单 List of Eastern Bloc agents in the United States，维诺那文件List of Americans in the Venona papers

3.FBI Memorandum identifying Harry Dexter White as agent Jurist （司法部调查结果）

4.Andrew, Christoper; Vasili Mitrokhin (1999), The Sword and the Shield: The Mitrokhin Archive and the Secret History of the KGB, New York: Basic Books, p. 106, ISBN 0-465-00310-9（俄方）

5.Alexander Vassiliev’s Notes and Harry Dexter White（俄方）